Thread: Hello everyone!

Came here looking for some help on my beloved GTP. Glad to be parts of what looks like a great forum. Any and all help greatly appreciated.

So here goes.


I am at a loss, I have searched everywhere. I have a semi built Turbo swapped 1997 GTP, Built the car myself, Tuned on HP tuner on a dyno twice.

Car put down great numbers. However I have a Random misfire and it seems to be at only Idle and worse when its warmed up. Most of the time does not throw a code, I took my Timing light to all wires and the misfires are only happening on the Back 3 Cylinders, 2-4 and 6.

1-3 and 5 fire great.

I have Swapped Plugs, Wired, ICM, PCM, New plugs gapped properly, 10.5 MM Wires,mCoil packs.... Even bought a complete matching 97 running parts car to swap parts off, I have done EVERYTHING. I can manually pull the wires off the coil packs and watch 2-4 and 6 misfire at the packs consistently.

Car pulls like a freight train WOT. But at Idle it randomly misses.

Maybe a cps? or a Cam position sensor? It seems that its somewhere between the Computer and the ICM.

Thoughts?

What would cause this on the back 3 Cylinders??

Appreciate the help.

No cam yet. Plugs are gapped at .32, tuned at 16.5 pounds. I know for sure it's not a compression issue, I watched the coil packs randomly misfire at the caps as I pulled the wires one by one, also used a timing light on each wire to watch the flash.

Autolite xp iridium from zzp. I had the plugs gapped at .50. But was told with such high boost I would get blow out. They said .32 would be best. Either way why only on the back 3 cylinders? They are all gapped the same. I will look at swapping the plugs for sure. Appreciate the ideas. No thoughts on the cam sensor? Crank sensor? Only codes I ever get is po300 and it's rare, but the misses are pretty much constant when warm.

Will do. Greatly appreciate all the wisdom.